Grinding wheel



Jan. 7. 1936. WEBSTER 2,027,132

GRINDING WHEEL Filed Dec 19, 1934 iiiii I I i ii'i riiiiiiiik i IX I\\ 1\N WITNESaEs DUANE E. WEBSTER cutting operation.

Patented Jan. 7, 1936 PATENT OFFICE GRINDING WHEEL Duane E. Webster,Worcester, Mass, assignor to Norton Company, Worcester, Mass, acorporation of Massachusetts Application December 19, 1934, Serial No.758,279 lo claims. (01. 51-206) This invention relates to a grindingwheel, and more particularly to a cutting-off wheel which is very thinin comparison to its diameter and adapted to be employed in the natureof 'a rotary saw for rapidly cutting deep narrow grooves or cutting offlengths of work.

Many of the present-day cutting operations which were formerlyaccomplished with rotary steel saws are now being done much more rapidlyand efficiently with cutting-off grinding wheels. These cutting-oilwheels, which are 20 inches or less in diameter and /8 of an inch orless in thickness, are provided with substantially flat,- parallel,opposed side faces and they depend solely upon the sharp abrasive grainsprojecting from the wheel periphery to perform the These wheels arefragile bodies and in view of the fact that they are very thin ascompared to their diameters, they cannot be subjected to any transversepressures. It is common practice for these wheels to rotate as fast as16,000 surface feet per minute. Hence,

wheel breakage during a cutting-off operation would not only seriouslyendanger the machine operator, but would probably cause spoilage of thework. i

Although these high speed cutting-01f wheels are capable of a veryfast-cutting operation as compared with the familiar type of circularsteel saws, the safe cutting rate is very much limited in comparisonwith the cutting ability of the wheel since insufficient opportunity isprovided for dissipation of the excessive heat of grinding.Consequently, many of these wheels are used at too high a speed and fedtoo' rapidly into the work, with the frequent result that the heat ofgrinding softens the wheel bond causing uneven stresses within thegrinding wheel and changing its abrading characteristics, therebywarping and often breaking the wheel and injuring the work as well asendangering the operator of the machine. Many of these thin cutting-offwheels tend to wear away most rapidly at their peripheral edges, causingthem to gradually become narrower in thickness at their periphery thanat their central portion. A grinding wheel worn in this manner rapidlybecomes wedge shaped and does not cut sufilcient clearance for itself asit enters the work, with the consequent result that it tends to bindwithin thework and break.

Even if a wheel which becomes worn in this manner does not break, itproduces an unsatisfactory cut which is not perpendicular to the axis ofwheel rotation.

Various wheel shapes have been employed in an endeavor to surmount thesedifficulties. For example, it has been contemplated to provide acutting-off grinding wheel having reentrant side faces which taper fromthe wheel periphery to the central wheel portion in order to providesufficient wheel clearance and prevent any tendency of binding of thewheel within the work. However, due to the inherent friability of arelatively thin cutting-off grinding wheel, it has been necessary tomake wheels of this type verymuch 10 wider with the consequent result ofwasting of material cut off and a much slower cutting operation.

It has further been contemplated to provide spaced grooves orindentations in the opposed 15 parallel fiat side faces of a cutting-01fwheel to aid in cooling it during grinding, but none of these expedientshas offered suflicient improvements to permit a wheel to be operatedwithin its maximum cutting ability. Furthermore, grooves andindentations in the opposed wheel faces have served to weaken the wheelsand prevent a high rotating speed.

It is, therefore, the primary object of this invention to provide agrinding wheel capable of cutting on its periphery and at the same timeabrading the side face of a work piece sufficiently to prevent excessiveheating and breakage of the wheel. 4

It is a further object of this invention to provide a thin cutting-offgrinding wheel having a side face of predetermined roughness composed ofa layer of projectingabrasive grains which may be of any desired shapeand size, irrespective of the size and shape of the abrasive grainswithin the main body portion of the wheel.

It is a still further object of this invention to provide a method ofmaking such a cuttingoff grinding wheel which may be easily andeconomically practiced and which serves to provide a highly efficientwheel capable of abrading the side faces of a work-cut during a grindingoperation to preventthe wheel from overheating and binding therein.

The accompanying drawing illustrates a cutting-oil. wheel having roughabrasive faces on both sides thereof, but it will be understood that theinvention applies equally well to any grinding wheel having only onerough face.

In thedrawing: I

Fig. 1 is a perspective view, partly broken away, to show the preferredembodiment of this invention; and

Fig. 2 shows one method of producing m preferred type of cutting-oilwheel.

According to this invention, I have provided a special type of grindingwheel which is particularly adapted for grinding up' to a shoulder on awork piece or for use as a cutting-off wheel which is required toproduce deep, narrow cuts and/or cut off lengths of work. Such a wheelmay comprise a main body portion of suitably bonded abrasive grains anda side face composed of a sheet or layer of material carrying abrasivegrains thereon which provide sharp, free cutting edges projectingtherefrom. In my preferred type of invention, a cutting-off wheel isprovided with rough side wheel faces composed of any suitable sheets ofabrasive material, such as an abrasive coated paper or other suitablefibrous material, which may be cemented to the side faces of the mainbody portion of the wheel and form an integral part therewith.' Thefibrous material preferably comprises a very thin, porous, waterproofpaper which may be integrally bonded to the main body portion of thewheel by the bond employed therein. The fibrous material also serves thefurther purpose of strengthening the cutting-off wheel as well as tosecure the sharp cutting abrasive grains on the side wheel faces andprovide opposed rough wheel faces composed entirely of sharp abrasivecutting edges projecting therefrom. If desired, these surface abrasivegrains may be oriented when they are located on their fibrous backing sothat their major axes will be opposed to the wheel faces and providewheel faces composed solely of long, sharp, protruding abrasive cuttingteeth projecting therefrom.

The abrasive grains on the side wheel faces may be of any desired shapeand size irrespective of the shape and size of the abrasive grainsbonded within the main body portion of the wheel.

As illustrated in the accompanying drawing, the preferred type of .myinvention comprises a laminated disk type of cutting-off wheel l0 havingtwo opposed side faces II and I2 of a predetermined roughness and,cutting ability and a peripheral grinding face I3 which is very narrowin comparison to its diameter. The main body portion of my grindingwheel is composed of an annular grinding member l4 comprising abrasivegrains, such ,ascrystalline alumina or silicon carbide, of suitable sizeand of a Work cut at an extremely rapid rate as the wheel enters thereinand thereby offer sufiicient clearance for the wheel to provide a fast,free cutting grinding wheel capable of feeding into the work at itsmaximum peripheral cutting capacity without overheating or causingdamage to either wheel or work. In order to provide a wheel having suchrapid, free cutting ability, the main body wheel portion M has its sidescoated with layers or sheets of sharp abrasive material l6 which areintegrally secured thereto and serve to provide opposed rough side wheelfaces composed entirely of sharp projecting abrasive grains which may beof any desired size and shape irrespective of the size and shape of theabrasive grains within the main body portion ll. Hence, the side wheelfaces may be constructed to abrade the sides of the work cut an abrasivecoated paper or any other suitable abrasive coated fibrous support whichmay be integrally bonded to the sides of the main wheel body portion M.This material is preferably very thin and porous, so that the cementingor adhesive material employed to secure it in position may enter thepore structure and integrally unite the surface abrasive grains inposition to provide side wheel faces composed entirely of sharp cuttingabrasive teeth, each of which has one or more protruding unobstructedfree cutting edges arranged to abrade the sides of a work cut as thewheel enters the work.

If desired, the abrasive coated fibrous ma-.

terial forming the side wheel faces l6 may be manufactured in such amanner that the individual abrasive grains are oriented and thereaftersecured in position'with their major axes opposed to their support, asdisclosed in the U. S. Patent to Schacht No. 1,854,071. It will beappreciated that a construction of this type will provide opposed wheelfaces of maximum roughness which are composed entirely of a ployed inawet grinding operation, if desired.

and the cementing material which secures the coating of abrasive grainsthereto may comprise any suitable adhesive. which will resist heat ofgrinding and the moisture of a wet grinding operation and integrallysecure the layers Hi to the main body portion [4.

The sheets of abrasive material l6 may be suitably secured to the sidesof the main body portion H by means of a cementitious'or adhesivematerial which intimately secures them as integral members therewith. Inmy preferred construction, the rough wheel sides l6 are integrallysecured to the main body portion of the wheel by the same bondingmaterial which secures the central abrasive grains into an integralgrinding unit. However, it will be appreciated that these abrasive sidefaces may be suitably secured in position by means of any It is notinsuitable cementitious material. tended, however, that the scope ofthis invention be limited to a grinding wheel having side faces composedof abrasive coated fibrous material. The present invention relates to anabrasive wheel having any suitable sheets of abrasive material appliedto the sides of the main body portion of the wheel by means of suitableadhesive or bond whereby the projecting abrasive grains forming sidewheel faces IE will be integrally united therewith.

One convenient method of producing my pre ferred type of grinding wheelis illustrated in Fig. 2 wherein a rigid bed 25 is arranged to support apress plate 26, retaining ring 28, and a hub -30. For convenience ofassembly, the hub 30 and the retaining ring 28 slidably engage the pressplate 26. A disk of sheet abrasive material such as an abrasive coatedfibrous material 32, and preferably an abrasive coated waterproof paperhaving a layer of abrasive grains of de- I able organic bondingmaterial, is then placed.

within the space between hub 30 and retaining ring 28 and in engagementwith the abrasive disk 32. A second abrasive disk similar in shape andconstruction to disk 32 is then lo-' cated between hub 30 and retainingring 28 with its fibrous support in engagement with the central annularbody 34 of abrasive and bond. thereby forming a laminated grinding wheelassembly having a central portion of abrasive and bond which is flankedwith side faces composed of layers of abrasive grains separatedtherefrom by thin sheets of fibrous material. A top press plate 38,slidably engageable with hub 30 and retaining ring 28, i placed upondisk 35 in engagement with abrasive coating thereon and suflicientpressure and heat are applied in any well-known manner to cause thebonding material within the central wheel portion 34 to soften and flowthrough the entire assembly and thereafter become matured, intimatelyuniting the abrasive disks 32 and 35 and forming an integral grindingwheel structure having the main body portion l4 flanked with thin sidefaces l6 (Fig. 1) composed entirely of sharp.

projecting abrasive grains which are of any desired shape and sizeirrespective of the grains within the main body portion of the wheel.

It will be appreciated that in a grinding wheel of this type, side facesmay be provided having any desired cutting ability. Hence, the

side'faces of the wheel may be arranged to abrade the work at asufiiciently rapid rate to provide a cutting-off wheel capable offeeding into the work at its maximum peripheral cutting ability. withoutdanger of binding or overheating. Various modifications in structure andin method of manufacture will be apparent to one skilled in the art, andthe claims are to be interpreted broadly within the scope of thisdisclosure.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. A grinding wheel comprising a main body portion of bonded abrasivegrainsshaped in the form of a disk, and a separately manufacsive grainshaving two opposed side faces and a peripheral face, and a thin sheet ofabrasive coated fibrous material cemented to each of the opposed sidefaces, forming rough wheel faces composed principally of sharp,projecting abrasive teeth which abrade the side faces of the work cutduring a grinding operation and prevent binding of the wheel therein.

4. A cutting-off grinding wheel adapted for producing deep, narrow cutscomprising a 5 bonded abrasive disk-shaped central body portion ofbonded abrasive grains having two opposed side faces and a very narrowperipheral face in comparison to its diameter, a thin, diskshaped sheetof waterproof fibrous material cov- 10 ering each'side wheel face andintegrally secured thereto by the same bond as that used in the centralbody portion, and layers of sharp abrasive grains cemented to thefibrous material which provide opposed rough side wheel faces 15composed principally of closely spaced, sharp, abrasive cutting edgesprojecting therefrom, serving to abrade the sides of the work cut andprevent binding of the wheel therein during rinding.

5. A cutting-off grinding wheel adapted for producing deep cutscomprising a disk shaped main body portion of bonded abrasive grains,"and opposed rough side wheel faces composed of sheets integrally unitedtherewith which have 25 layers of abrasive grains bonded thereto withtheir major axes projecting outwardly from the wheel faces and providingclosely spaced, sharp cutting abrasive teeth projecting therefrom.

s. A cutting-off grinding wheel adapted for to producing deep cutscomprising a disk shaped ,main body portion of bonded, abrasive grains,

' face and providing closely spaced, sharp cutting teeth evenly disposedover theentire wheel face. 40 '7. The method of producing a grindingwheel comprising the steps of providing a disk of fibrous materialhaving a coating of abrasive grains integrally cemented thereon andsharp cutting abrasive teeth projecting therefrom, placing a layer of anunmatured mixture of abrasive grains and a bond in engagement with thesheet of fibrous material, and subjecting the assembly to the influenceof suflicient heat and pressure to cause the bondto unite the entiremass together as amintegral inember and providea grinding wheel having ardugh'side face composed principally of projecting abrasive grainshaving free cutting edges.

8. The method of producing a cutting-oi! grinding wheel comprising thesteps of providing two. thin disks of sheet fibrous material, each' ofwhich has a coating of abrasive grains integrally cemented thereon andsharp abrasive cutting edges projecting therefrom, placing an annularbody of an unmatured mixture of abrasive grains and an organic bondbetween the sheets of fibrous material, and subjecting the assembly tothe influence of sufiicient heat and pressure to cause the bond to unitethe entire mass as an integral member and provide a thin grinding wheelhaving opposed rough side faces composed principally of projectingtooth-like abrasive grains having free cutting edges.

9. The method of producing a grinding wheel comprising the steps ofcoating a disk of thin fibrous material with an adhesive, depositing alayer of granular abrasive material thereon, orienting said abrasivegrains so that they are integrally secured to the fibrous support withtheir major axes projecting outwardly therefrom, placing an unmaturedmixture of abrasive grains and bond in engagement with the fibrousmaterial to form the main body of the wheel, and subjecting theassembled material to the influence of sufficient heat and pressure tounite the entire mass and provide a grinding wheel having a rough sideface principally composed of projecting abrasive grains which may be ofany desired size and shape irrespective of the abrasive grains withinthe main body portion of the wheel.

10. The method of producing a cutting-off grinding wheel comprising thesteps of coating a sheet of thin, porous fibrous material with adhesive,depositing a layer of granular abrasive material thereon, orienting theabrasive grains so that they are secured to the fibrous support withtheir major axes projecting outwardly therefrom, shaping the coatedfibrous material in the form of two disks, each of which has thediameter of the desired grinding wheel, placing a body of an unmaturedmixture of abrasive grains and an organic bond in engagement with thefibrous disks, and subjecting the assembly to the influence ofsufilcient heat and pressure to cause the bond to flow into the pores ofthe fibrous material and intimately unite the entire 10 shape and sizeirrespective of the shape and size 16 of the abrasive grains within themain body portion of the grinding wheel.

DUANE E. WEBSTER.

